In the recent past the perfection of the optical fiber as a means of transmitting light has brought about many innovations in the decorative and technical arts. From the very beginnings of the optical fiber industry, it has been recognized that the bundle of optical fibers presents an excellent method of magnifying or expanding images. By maintaining the fibers at one end of the cable in a close relationship to receive a small image and spreading the fibers at the other end to produce a large image, it is possible to magnify pictures of various kinds. Naturally, the light entering at the small end must be quite intense in order to obtain an image at the other end which is capable of being seen. However, a major problem is encountered in the fact that, in order that the image appear exactly the same at the large end as it was when it was received at the small end, the fibers must be spread in exactly the same pattern as exists at the small end. Although this can be accomplished manually, it is a very difficult operation to perform in a production setting. For instance, it has always been a desirable technical feat to magnify a television image; at the present time, this function is accomplished by the use of a projection lens. This means, however, that the input cathode-ray tube must produce a very intense image, because the amount of light that is generated is spread out over a large area and, therefore, becomes weaker. The use of an intense television image generates a large amount of heat, so that substantial cooling of the CRT and related equipment is necessary. In accomplishing the same function with optical fibers, the advantages are obvious. For one thing, the fibers can be arranged on a flat screen held against the wall. However, the problem is still one of arranging the output fibers in exactly the same pattern and arrangement as the input ends of the fibers; this has been a production feat that has been insolvable. Another major problem has been that the output end of the fibers, which generally has an interface with a low index-of-refraction medium, such as air, allows reflective and refractive interactions which do not promote the most efficient use of the input light for viewing. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
It is, therefore, an outstanding object of the invention to provide optical apparatus that contains a plurality of optical fibers in which the input fiber arrangement and the output fiber arrangement are exactly the same, but the output fibers are spaced further apart.
Another object of this invention is the provision of optical apparatus for enlarging or expanding a visual image without distortion.
A further object of the present invention is the provision of a method of arranging optical fibers so that the input pattern and the output pattern are very accurately the same.
A still further object of the present invention is the provision of an image expanding apparatus which directs the major portion of the output light toward the viewer, with minimal reflective and refractive loss at the output end of the fibers.
It is another object of the instant invention to provide an optical image expander which is simple in construction, which is inexpensive to manufacture, and which is capable of a long life of useful service with a minimum of maintenance.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.